Geology topics

Daniel C. White

Publications and source records attributed to Daniel C. White.

4 recordsLinked to original sources

USGS2026

Bank-dwelling beavers contribute to the wood regime in a dryland river

Our findings suggest that the influence of dwelling beavers on large wood budgets may substantially determine the structure and function of medium to large rivers, particularly in dryland systems such as the White River. Recognizing the role of bank-dwelling beavers expands our understanding of biotic drivers of riverscape complexity and provides new opportunities to integrate ecology with fluvial geomorphology in managing and restoring dynamic river corridors.

Utah↗

USGS2026

Estimating discharge from undular hydraulic jumps: Feasibility assessment based on flume experiments

Rapids are common in steep rivers, often forming where flow transitions from supercritical (Froude number, Fr > 1) to subcritical ( Fr < 1) through a hydraulic jump. When upstream Fr is supercritical but close to 1, this transition may occur as an undular hydraulic jump, exhibiting a train of stationary waves downstream of the jump toe. Previous studies proposed a method to estimate discharge using only UHJ wave spacing and channel width combined with a wave dispersion equation for large water depths relative to the UHJ wavelength. This method is based on the hypotheses that, by their presence, UHJs indicate near-critical flow conditions ( Fr ≈ 1) and that wave celerity c is equal to and opposite the cross-sectionally averaged flow velocity U . However, these hypotheses have not been thoroughly tested. We used data from published UHJ flume experiments to test the hypotheses that Fr ≈ 1 and c = U , compare the deep-water and general wave dispersion equations, and evaluate the accuracy of discharge estimates. In these experiments, the stationary waves exhibited shallow depths relative to wavelength and flow was subcritical ( Fr < 1) when averaged across multiple wavelengths. Additionally, wave celerity more closely approximated the surface flow velocity than U . By using a Fr representative of actual conditions and applying a coefficient to correct for c ≠ U , the accuracy of the discharge estimates improved. This finding suggests that the critical flow-based method is robust and can produce reliable streamflow estimates if the remotely observed wave trains are correctly interpreted as UHJs, without requiring in situ measurements.

Water Resources Research↗

USGS2025

Remote sensing of river discharge based on critical flow theory

Critical flow theory provides a physical foundation for inferring discharge from measurements of wavelength and channel width made from images. In rivers with hydraulically steep local slopes greater than ∼0.01, flow velocities are high and the Froude number F r (ratio of inertial to gravitational forces) can approach 1.0 (critical flow) or greater. Under these conditions, undular hydraulic jumps (UHJ's) can form as standing wave trains at slope transitions or constrictions. The presence of UHJ's indicates that mean F r ≈ 1, implying that the velocity and depth of the flow and the spacing of the waves are uniquely related to one another. Discharges estimated from 82 Google Earth images agreed closely with discharges recorded at gaging stations ( R 2 = 0.98), with a mean bias of 1% ± 11%. This approach could provide reliable discharge information in many fluvial environments where critical flow occurs, which tend to be underrepresented in gage networks

Geophysical Research Letters↗

USGS2023

Climate change impacts on native cutthroat trout habitat in Colorado streams

Headwater streams support vital aquatic habitat yet are vulnerable to changing climate due to their high elevation and small size. Coldwater fish are especially sensitive to the altered streamflow and water temperature regimes during summer low flow periods. Though previous studies have provided insights on how changes in climate and alterations in stream discharge may affect habitat availability for various native cutthroat trout species, suitable physical habitats have not been evaluated under future climate projections for the threatened Greenback Cutthroat Trout (GBCT) native to headwater regions of Colorado, USA. Thus, this study used field data collected from selected headwater streams across the current distribution of GBCT to construct one-dimensional hydraulic models to evaluate streamflow and physical habitat under four future climate projections. Results illustrate reductions in both predicted streamflow and physical habitat for all future climate projections across study sites. The projected mean summer streamflow shows greater decline (−52% on average) compared to the projected decline in mean August flow (−21% on average). Moreover, sites located at a relative higher elevation with larger substrate and steeper slope were projected to experience more reductions in physical habitat due to streamflow reductions. Specifically, streams with step-pool morphologies may experience grater changes in available habitat compared to pool-riffle streams. Future climate change studies related to coldwater fish that examine spatial variation in flow alteration could provide novel data to complement the existing literature on the thermal characteristics. Tailoring reintroduction and management efforts for GBCT to the individual headwater stream with adequate on-site monitoring could provide a more holistic conservation approach.

Colorado↗